GUIDELINES FOR THE

PROTECTION AND MANAGEMENT

OF

AQUATIC SEDIMENT QUALITY

IN ONTARIO

AUGUST 1993

Ministry of

Environment

and Energy

ISBN 0-7778-9248-7

GUIDELINES

FOR THE PROTECTION AND MANAGEMENT

OF AQUATIC SEDIMENT QUALITY IN ONTARIO

AUGUST 1993

REPRINTED MARCH 1994REPRINTED JUNE 1994

REPRINTED SEPTEMBER 1994REPRINTED JANUARY 1996

Cette publication techniquen'est disponible qu'en anglais.

Copyright: Queen's Printer for Ontario, 1993This publication may be reproduced for non-commercial purposes

with appropriate attribution.

FIBS 1962

GUIDELINES FOR THE PROTECTION AND MANAGEMENT OF AQUATIC

SEDIMENT QUALITY IN ONTARIO

Report prepared by:D. Persaud and R. Jaagumagi

Standards Development Branch

and

A. HaytonEnvironmental Monitoring and Reporting Branch

ACKNOWLEDGEMENT

The authors are grateful to MOE Regional and head office staff and the AdvisoryCommittee on Environmental Standards (ACES) for their valuable comments and suggestions.Special thanks go to Les Fitz, Art Roy and Jim Fry whose extensive comments and suggestionsproved invaluable throughout the developmental process.

Financial assistance and technical advice were provided by Environment Canada throughthe Polluted Sediment Committee of the Canada-Ontario Agreement. These contributions aregratefully acknowledged.

i

TABLE OF CONTENTS

EXECUTIVE SUMMARY iv

Foreword 1

SECTION 1 BACKGROUND 1

SECTION 2 SEDIMENT QUALITY GUIDELINES 2

SECTION 3 APPLICATION OF THE SEDIMENT QUALITY GUIDELINES 63.1 The Evaluation Process 6

3.1.1 General Conditions Governing Evaluation 63.2 Specific Applications 8

3.2.1 Placement of Fill Directly into a Watercourse 83.2.2 Areas of Potential Concern 83.2.3 Dredged Material Disposal 103.2.4 Spills Clean-up 11

SECTION 4 PROTOCOL FOR SETTING SEDIMENT QUALITY GUIDELINES 114.1 Rationale For Setting Sediment Quality Guidelines 114.2 Approaches to Sediment Quality Guideline Development 12

4.2.1 Sediment Background Approach 134.2.2 Equilibrium Partitioning Approaches 134.2.3 Apparent Effects Threshold Approach (AET) 154.2.4 The Screening Level Concentration Approach (SLC) 164.2.5 Spiked Bioassay Approach 18

4.3 Summary Evaluations of the Various Approaches to SQG Development 184.4 Calculation of Sediment Quality Guidelines 20

4.4.1 The No Effect Level 204.4.2 The Lowest Effect Level 214.4.3 The Severe Effect Level 22

4.5 Data Requirements 22

References 23

ii

LIST OF TABLES

Table 1 Guidelines for Metals and Nutrients 3

Table 2a Guidelines for PCBs and Organochlorine Pesticides 4

Table 2b Guidelines for Polycyclic Aromatic Hydrocarbons 5

Table 3 Additional Parameters 6

Table 4 Background Levels for the Metals 7

Table 5 Background Sediment Concentrations of Organic Compounds 7

LIST OF FIGURES

Figure 1 Screening Level Concentration Calculation

Figure 2 Application of the Provincial Sediment Quality Guidelines to Sediment Assessment

Figure 3 Application of the Provincial Sediment Quality Guidelines to Dredging Activities

iii

EXECUTIVE SUMMARY

The background

Contaminated sediment has been singled out as a major environmental problem. The concern is thatpersistent toxic substances - poisonous substances that take a long time to break down - in the sedimentwill accumulate in carp, catfish and other bottom-dwelling fish as well as in the bottom-dwelling organisms,such as worms and midges, that live in the sediments. These contaminants may be transferred to fish eitherbecause they have fed on the organisms or come into contact with the sediments. These chemicals maybe transferred again to wildlife, birds and people who eat the fish. This process, by which organisms canaccumulate levels of persistent chemicals higher than in sediments or water, is called biomagnification.

The source

The primary source of contaminants in sediments is toxic chemicals from industrial and municipaldischarges of waste water. The runoff from cities, towns and agricultural areas may also contribute to theproblem. Other sources include:

! Lakefilling or the practice of creating more land by building up the shoreline with rubble, bricks,stones, concrete and loose earth may also add to the problem unless the fill is free of contaminants.

! Chemicals in factory emissions which, attaching themselves to particles of dust or droplets of water,fall back to the earth in the form of dust, rain, sleet, hail or snow.

The response

The ministry has several programs in place which, either directly or indirectly, tackle the problemof contaminated sediment.

! The Municipal Industrial Strategy for Abatement (MISA) - The aim of the program is to reducedrastically the discharges of toxic chemicals from industry and municipalities either by improvingtreatment plants or by changing industrial processes so that toxic chemicals are no longer needed.

! The Remedial Action Plan (RAP) Program - The aim of the program is to help clean up the 17 Areasof Concern in Ontario identified by the International Joint Commission as being badly contaminated.The RAP teams have identified contaminated sediment as one of the factors contributing to poorwater quality and living conditions for the sediment dwelling organisms - also known as the benthiccommunity.

! Operation Lifelines and the Beaches Improvement Program - The aim of these programs is to helpmunicipalities improve storm water management and reduce the amount of runoff from cities andtowns.

! Fill Quality Guidelines for Lakefilling in Ontario - The aim of the guidelines is to protect the qualityof the aquatic habitat. The guidelines regulate the quality of fill used, based on the ProvincialSediment Quality Guidelines and the Provincial Water Quality Objectives/Guidelines.

The Sediment Quality Guidelines

The purpose of the Sediment Quality Guidelines is to protect the aquatic environment by setting safelevels for metals, nutrients (substances which promote the growth of algae) and organic compounds.

The guidelines replace the ministry's 1976 Open Water Disposal Guidelines. Those guidelinesoriginally were developed to determine whether or not dredged material was suitable for disposal in openwater. Over time their use was expanded to include all aspects of sediment assessment.

The guidelines are designed to help environmental managers - ministry officials and environmentalconsultants - make decisions on a whole range of issues that affect the quality of sediment. For example,the guidelines will be used by RAP teams to determine which sediments are contaminated and how tomanage the problem most effectively.

iv

How the guidelines work

The guidelines establish three levels of effect - No Effect Level, Lowest Effect Level and Severe EffectLevel. The Lowest Effect level and Severe Effect Level are based on the long-term effects which thecontaminants may have on the sediment-dwelling organisms The No Effect Level is based on levels ofchemicals which are so low that no contaminants are passed through the food chain.

The levels of effect are designed to help environmental managers determine:

! when sediment may be considered clean;

! what levels of contamination are acceptable for short periods of time while the source of thecontamination is being controlled and cleanup plans are being developed;

! what levels of contamination are considered severe enough to consider the possibility ofeither removing the sediment or covering it with a layer or two of cleaner sediment. This iscalled capping.

The three levels of effect are:

! The No Effect Level: This is the level at which the chemicals in the sediment do not affectfish or the sediment-dwelling organisms. At this level no transfer of chemicals through thefood chain and no effect on water quality is expected.

Sediment that has a No Effect Level rating is considered clean and no management decisionsare required. Furthermore, it may be placed in rivers and lakes provided it does notphysically affect the fish habitat or existing water uses - for example a water intake pipe.

! The Lowest Effect Level: This indicates a level of contamination which has no effect on themajority of the sediment-dwelling organisms. The sediment is dean to marginally polluted.Dredged sediments containing concentrations of organic contaminants - PCBs or pesticides,for example - that fall between the No Effect Level and the Lowest Effect Level may not bedisposed of in an area where the sediment at the proposed disposal site has been rated atthe No Effect Level or better.

Contamination in sediment that exceeds the Lowest Effect Level may require further testingand a management plan.

! The Severe Effect Level: At this level, the sediment is considered heavily polluted andlikely to affect the health of sediment-dwelling organisms. If the level of contaminationexceeds the Severe Effect Level then testing is required to determine whether or not thesediment is acutely toxic.

At the Severe Effect Level a management plan may be required. The plan may includecontrolling the source of the contamination and removing the sediment.

For more copies of the new Provincial Sediment Quality Guidelines, please contact the Ministry ofthe Environment, Public Information Centre, 135 St. Clair Ave. W., Toronto, Ont. M4V 1P5, (416) 323-4321.

v

FOREWORD

The guidelines provided in this document were developed for use in evaluating sediments throughoutOntario, and replace the Open Water Disposal Guidelines (published by the Ministry in 1976) currently usedfor sediment evaluation. The Provincial Sediment Quality Guidelines (PSQGs) are intended to provideguidance during decision-making in relation to sediment issues, ranging from prevention to remedial action.

The document provides a background to the PSQG development, the PSQGs, the application of theguidelines to sediment evaluation and the protocol used in establishing the guidelines. Companion volumesto the document (Jaagumagi 1992a, 1992b) provide more details on the actual derivation of the numericvalues for various parameters.

SECTION 1

BACKGROUND.

Contaminated sediment has been singledout as a major environmental concern in manyareas of Ontario, especially the Great Lakes (IJC1985). Persistent toxic substances that haveaccumulated in bottom sediments from industrial,municipal and non-point sources are a threat tothe survival of bottom-dwelling (benthic)organisms and their consumers, and can alsoimpair the quality of the surrounding water.

Sediments contaminated by suchsubstances have become a critical problem forenvironmental managers. In order to dealeffectively with sediment contamination problems,managers need to know at what levelscontaminants pose no risk to sediment-dwellingorganisms as well as other water uses, and atwhat levels contaminants are detrimental toaquatic biota, At present, management decisionsare seriously hampered due to a lack of criteriawhereby acceptable and unacceptable levels ofcontaminants in sediments can be defined. Adefinition of sediment contamination needs to bedeveloped before strategies for the managementof contaminated sediments can be implemented.

Routine evaluation of the significance ofcontaminants in sediments is currently a difficulttask because of the lack of adequate guidelines.The Open-Water Disposal Guidelines, developedduring the early 1970's (Persaud & Wilkins 1976),were not designed to address the significance ofcontaminants in in situ sediment but weredesigned exclusively for the evaluation of dredgedmaterial for open-water disposal and onlyincidentally provide general guidance onenvironmental protection.

The need for biological effects-basedguidelines for the evaluation of sediment is well recognized. Current sediment related issues aremuch broader than those identified in the early1970's and knowledge based on informationaccumulated over the last decade or so requiresthat strategies be developed to manage sediment.Guidelines for the evaluation of sediment mustprovide the basis for determining when sedimentsare considered clean, what levels of contaminationare acceptable in the short-term, and whencontamination is severe enough to warrantsignificant remedial action.

The Provincial Sediment Quality Guidelinesdescribed in this document are a set of numericalguidelines developed for the protection of aquaticbiological resources. These biologically basedguidelines have been derived to protect thoseorganisms that are directly impacted bycontaminated sediment, namely thesediment-dwelling (benthic) species. To protectagainst biomagnification of contaminants throughthe food chain from sediment contaminantsources, as well as other water quality concerns(e.g., recreational uses), the Ministry has reliedon Provincial Water Quality Objectives/ProvincialWater Quality Guidelines (PWQO/PWQGs) as thebasis for deriving sediment values that ensurethese objectives and guidelines are not exceededas a result of sediment contamination. Thederivation of the PWQO/PWQGs is explained indetail in OMOE (1990).

The Sediment Quality Guidelines tabled inthe document have been designed such that theyare consistent with the goals and policies for themanagement of surface waters that the Ministryhas detailed in its handbook, Water Management:Goals, Policies, Objectives and ImplementationProcedures of the Ministry of the Environment(MOE, 1984).

1

SECTION 2

SEDIMENT QUALITY GUIDELINES

The essence of the guideline levels andtheir significance are provided below. Theguidelines as set out define three levels ofecotoxic effects and are based on the chronic,long term effects of contaminants on benthicorganisms. These levels are:

1. A No Effect Level at which no toxiceffects have been observed onaquatic organisms. This is the levelat which no biomagnificationthrough the food chain is expected.Other water quality and use

guidelines will also be met at thislevel.

2. A Lowest Effect Level indicating alevel of sediment contaminationthat can be tolerated by themajority of benthic organisms.

3. A Severe Effect Level indicating thelevel at which pronounceddisturbance of the sediment-dwelling community can beexpected. This is the sedimentconcentration of a compound thatwould be detrimental to themajority of benthic species.

2

Details on these levels, and the protocolsused in developing the guidelines are provided insection 4 of this document.

The No Effect and Lowest Effect guidelinescompare closely with the lowest or no effect levelsdetermined through a review of sediment toxicitybioassays by National Oceanic and AtmosphericAdministration (NOAA) (Long and Morgan, 1990).

As is discussed in Section 4.4, it is notcurrently possible to calculate a No Effect valuefor all parameters. Where this is the case for themetals, an interim value based on the lower of thebackground or Lowest Effect Levels will be used asa lower practical limit for management decisions.For the organics, the background values in Table5 define the lower practical limit for managementdecisions.

Table 1: Provincial Sediment Quality Guidelines for Metals and Nutrients. (values* in µg/g (ppm) dry weight unless otherwise noted)

METALS No Effect Level

Lowest EffectLevel

Severe EffectLevel

Arsenic - 6 33Cadmium - 0.6 10Chromium - 26 110Copper - 16 110Iron (%) - 2 4Lead - 31 250Manganese - 460 1100Mercury - 0.2 2Nickel - 16 75Zinc - 120 820

NUTRIENTS

TOC (%) - 1 10TKN - 550 4800TP - 600 2000

* - values less than 10 have been rounded to 1 significant digit. Values greater than 10 have beenrounded to two significant digits except for round numbers which remain unchanged (e.g., 400).

*-* - denotes insufficient data/no suitable method.

TOC - Total Organic Carbon TKN - Total Kjeldahl Nitrogen TP - Total Phosphorus

(June 1992)

3

Table 2a: Provincial Sediment Quality Guidelines for PCBs and Organochlorine Pesticides.(values a in µg/g (ppm) dry weight unless otherwise noted)

Compound No Effect Level Lowest EffectLevel

Severe Effect Level (µg/g organic carbon)*

Aldrin - 0.002 8BHC - 0.003 12α-BHC - 0.006 10β-BHC - 0.005 21γ-BHC 0.0002 (0.003)b (1) c

Chlordane 0.005 0.007 6DDT(total) 0.007 12op+ pp-DDT - 0.008 71pp-DDD - 0.008 6pp-DDE - 0.005 19Dieldrin 0.0006 0.002 91Endrin 0.0005 0.003 130HCB 0.01 0.02 24Heptachlor 0.0003 - -Hept. epoxide - 0.005b 5 c

Mirex - 0.007 130PCB(total) 0.01 0.07 530PCB 1254 d - (0.06)b (34) c

PCB 1248 d - (0.03)b (150) c

PCB 1016 d - (0.007)b (53) c

PCB 1260 d - (0.005)b (24) c

Lowest Effect Levels and Severe Effect Levels are based on the 5th and 95th percentiles respectively of theScreening Level Concentration (SLC) (see Section 4.2.4) except where noted otherwise.

( ) Denotes tentative guidelines

a - Values less than 10 have been rounded to 1 significant digit. Values greater than 10 have beenrounded to 2 significant digits except for round numbers which remain unchanged.

b - 10% SLC.

c - 90% SLC.

d - Analyses for PCB Aroclors are not mandatory unless specifically requested by MOE.

- Insufficient data to calculate guideline.

* Numbers in this column are to be converted to bulk sediment values by multiplying by the actualTOC concentration of the sediments (to a maximum of 10%), e.g. analysis of a sediment samplegave a PCB value of 30 ppm and a TOC of 5%. The value for PCB in the Severe Effects column isfirst converted to a bulk sediment value for a sediment with 5% TOC by multiplying 530 x 0.05 =26.5 ppm as the Severe Effect Level guidelines for that sediment. The measured value of 30 ppmis then compared with this bulk sediment value and is found to exceed the guideline.

(March 1993)

4

Table 2b: Provincial Sediment Quality Guidelines for Polycyclic Aromatic Hydrocarbons.(values in µg/g (ppm) dry weight unless otherwise noted)

Compound No Effect Level

Lowest EffectLevel

Severe Effect Level(µg/g organic

carbon)*Anthracene - 0.220 370Benz[a]anthracene - 0320 1,480Benzo[k]fluoranthene - 0.240 1,340Benzo[a]pyrene - 0.370 1,440Benzo[g,h,i]perylene - 0.170 320Chrysene - 0.340 460Dibenzo[a,h]anthracene - 0.060 130Fluoranthene - 0.750 1,020Fluorene - 0.190 160Indeno[1,2,3-cd]pyrene - 0.200 320Phenanthrene - 0.560 950Pyrene - 0.490 850PAH (total) - 4 10,000

(Guidelines could not be calculated for Acenaphthene, Acenaphthylene, Benzo[b]fluorene and Naphthalenedue to insufficient data. These will be calculated when sufficient data is available.)

Lowest Effect Levels and Severe Effect Levels are based on the 5th and 95th percentiles respectively of theScreening Level Concentration (SLC) (see Section 4.2.4) except where noted otherwise.

- Insufficient data to calculate guideline.

* Numbers in this column are to be converted to bulk sediment values by multiplying by the actual TOCconcentration of the sediments (to a maximum of 10%), e.g. analysis of a sediment sample gave a B[a]Pvalue of 30 ppm and a TOC of 5%. The value for B[a]P in the Severe Effects column is first converted toa bulk sediment value for a sediment with 5% TOC by multiplying 1443 x 0.05 = 72 ppm as the SevereEffect Level guideline for that sediment. The measured value of 30 ppm is then compared with this bulksediment value and is found to not exceed the guideline.

PAH (total) is the sum of 16 PAH compounds: Acenaphthene, Acenaphthylene, Anthracene,Benzo[k]fluoranthene, Benzo[b]fluorene, Benzo[a]anthracene, Benzo[a]pyrene, Benzo[g,h,i]perylene,Chrysene, Dibenzo[a,h]anthracene, Fluoranthene, Fluorene, Indeno[1,2,3-cd]pyrene, Naphthalene,Phenanthrene and Pyrene.

(March 1993)

5

Table 3: Additional Parameters.

Parameters carried over from the Open WaterDisposal Guidelines.

Oil and Grease 0.15%Cyanide 0.1 ppmAmmonia 100 ppmCobalt 50 ppmSilver 0.5 ppm

Routine testing for these parameters wouldnot be required but may be requested on acase-specific basis.

(June 1992)

SECTION 3

APPLICATION OF THE SEDIMENTQUALITY GUIDELINES

The Provincial Sediment Quality Guidelines(PSQGs) shown in Tables 1 and 2 supersede theOpen-Water Disposal Guidelines and will providethe basis for all sediment (or potential lakefillmaterials to be placed in water) evaluations inOntario. The guidelines pertain mainly to activitieswithin the aquatic environment and adherence tothem is not to be construed as exemption fromthe requirements of other guidelines, policies, orregulations of this Ministry or other agencies (e.g.,the placement of contaminated sediment at anupland site or facility will be subject to therequirements of the Ministry's Waste ManagementRegulations). The PSQGs will be used in makingdecisions on a number of sediment-related issuesranging from prevention of sedimentcontamination to remedial action for contaminatedsediment. Issues to be addressed include, but arenot limited to, the following:

! Determination of fill quality for lakefillingassociated with shoreline developmentprograms.

! Evaluation of sediment quality.

! Determination of appropriate action withregard - to sediment clean-up in areaswith historic sediment contamination suchas IJC Areas of Concern as well as otherareas of potential impact.

! Determination of the suitability of dredgedmaterial for open-water disposal.

! Establishing the chemical suitability ofsubstrate material for the restoration ofbenthic habitat.

! Determination of the appropriate degree ofsediment clean-up as a result of chemicalspills or unauthorized discharge.

3.1 THE EVALUATION PROCESS

Initial evaluation of bottom sediment or fillmaterial is conducted by comparing the chemicalconcentrations of the material to the appropriateparameter values listed in Tables 1 and 2a, andwhere required Tables 4 and 5, based onconditions described in section 3.1.1. Chemicalanalysis for compounds listed in Table 2b will beperformed where specifically requested by MOE orwhere there is reason to suspect contamination byPAH compounds. Provincial Sediment QualityGuidelines could not be calculated for theparameters in Table 3. Since these parameterscan be of concern in protecting aquatic biologicalrestiuices, the Open Water Disposal Guidelines willcontinue to be used though chemical analysis forthese parameters will be performed only wherespecifically requested by MOE. The Open WaterDisposal Guidelines are equivalent to the LowestEffect Level in terms of management decisions.

3.1.1 General Conditions Governing Evaluation

(a) Material will be tested by bulk sedimentanalyses and results reported on a dryweight basis (MOE Analytical Methods(MOE 1983) or MOE approved equivalentanalytical procedures to be used).

!(b) For the purposes of sediment or fill quality

evaluation, actual analytical resultsreported by the performing laboratorymust be provided. However, in comparingthe results with the parameter values inthe guidelines the results will be roundedas follows: if the reported value is lessthan ten, it will be rounded to onesignificant digit. Values greater than 10will be rounded to two significant digits.Round numbers remain unchanged.

6

e.g. Reported Value Rounded Value

<10 1.78 20.0364 0.040.0052 0.005

>10 10.827 11128.4 130

(c) If all parameter values for a given materialare at or below the No Effect LevelGuidelines, that material passes theguideline and it is anticipated that thematerial will have no adverse chemicaleffects on aquatic life or water quality.

(d) If a single parameter value for a givenmaterial, based on a sampling program,exceeds the No Effect Level Guideline butis below the Lowest Effect Level Guideline,the material fails the No Effect LevelGuidelines and would be considered ashaving a negligible potential to impair theaquatic environment.

(e) If a single parameter value for a givenmaterial, based on a sampling program, isat or above the Lowest Effect LevelGuidelines, that material fails the guidelineand it is anticipated that such materialmay have an adverse effect on somebenthic biological resources. If all values are below the Lowest Effect LevelGuidelines, no significant effects onbenthic biological resources areanticipated.

(f) If any single parameter value for a givenmaterial, as determined by a samplingprogram, is at or above the Severe EffectLevel Guideline, that material is consideredhighly contaminated and will likely have asignificant effect on benthic biologicalresources.

(g) The Ministry recognizes that in an area asgeologically diverse as Ontario, localnatural sediment levels of the metals mayvary considerably and in certain areas,such as wetlands, the organic mattercontent and nutrient levels may benaturally high.

METALS: In areas where local backgroundlevels are above the Lowest Effect Level,the local background level will form the

practical lower limit for managementdecisions. In some waterbodies surficial

Table 4: Background Levels for the Metals

Metal Background(µg/g)

Arsenic 4.2Cadmium 1.1Chromium 31Copper 25Iron (%) 3.12Lead 23Manganese 400Mercury 0.1Nickel 31Zinc 65Values are based on analyses of GreatLakes pre-colonial sediment horizon.

(June 1992)

Table 5: Background SedimentConcentrations* of OrganicCompounds.

Compound Background(µg/g dry wt.)

Aldrin 0.001α-BHC 0.001β-BHC 0.001γ-BHC 0.001Chlordane 0.001DDT (total) 0.01 op+ pp DDT 0.005pp-DDD 0.002pp-DDE 0.003Dieldrin 0.001Endrin 0.001HCB 0.001Heptachlor 0.001Heptachlor epoxide 0.001Mirex 0.001PCB (total) 0.02

* Values are based on the highest of theLake Huron or Lake Superior meansurficial sediment concentrations.

(June 1992)

7

sediments upstream of all discharges may beacceptable for calculation of backgroundvalues. Where it cannot be shown that suchareas are unaffected by local discharges, thepre-colonial sediment horizon is used. Sitespecific background for metals is calculatedas the mean of 5 replicate samples fromsurficial sediment that has not been directlyaffected by man's activities or from the'pre-colonial' sediment horizon. Thecalculations are described in Section 4 of thisdocument. Alternatively, the meanbackground values for the Great Lakes Basinas presented in Table 4 may be used.

NUTRIENTS: Areas of high natural organicmatter content, such as marshes and othertypes of wetlands, can be readilydistinguished from those resulting fromanthropogenic sources. In such cases, for thenutrients listed in Table 1, the localbackground would serve as the practicallower limit for management action.

(h) It is also recognized that long-range sourcessuch as atmospheric deposition havecontributed to accumulation of organiccompounds in areas remote from any specificsource. Therefore, in those areas wherespecific sources cannot be determined, thepractical lower limit for management actionis the Upper Great Lakes deep basin surficialsediment concentration. These have beendefined for a number of organic compoundsand are presented in Table 5.

3.2 SPECIFIC APPLICATIONS

3.2.1 Placement of Fill Directly into a Water-course

Fill refers to any type of solid material, otherthan those defined as inert (i.e., chemically clean)under MOE's Waste Management Guidelinesdescribed in Regulation 309 of the EnvironmentalProtection Act, used in shoreline or nearshoredevelopment programs generally referred to aslakefilling.

As a minimum, chemical analyses shall becarried out for the Mandatory Parameters listed in the Fill Quality Guidelines (Hayton et al. 1992). Inaddition, chemical analysis may be required forsome or all of the parameters in Tables 1, 2 and

3 on a site-specific basis.

Fill material equal to, or better than, the NoEffect Level Guidelines can be used withoutrestriction in a watercourse.

The conditions governing fill that exceed theNo Effect Level are outlined in MOE's guidelines onlakefilling (Hayton et al 1992).

3.2.2 Areas of Potential Concern

When sediment quality in an areaconsistently exceeds the Lowest Effect LevelGuideline, subject to the conditions in 3.1.1.(g)above, that area shall be considered as an area ofpotential concern, and the actions outlined belowshall apply. The sediment evaluation procedure isshown in Figure 2.

In areas where contaminants in sediment areat or above the Lowest Effect Level, steps shouldbe taken to control all point and non pointcontaminant sources to the area. Considerationwill be given to the provisions governing areas ofhigh mineralization and atmospheric deposition asoutlined in section 3.1.1.(g) and (h).

Application of Provincial Sediment QualityGuidelines to Sediment Assessment

The sediment evaluation procedure describedbelow outlines in detail the procedure in Figure 2.

1. The sediment concentrations for allparameters, based on a sampling program,are compared to the PSQGs. Theconcentrations of each parameter arecompared to each of the guideline levels.

1a. If sediment analysis shows that theconcentration of that parameter is below theNo Effect Level, the sediment can beconsidered as clean and no furthermanagement decisions are required.

2. If the sediment concentration of a parameterexceeds the No Effect Level but is below theLowest Effect Level then no furthermanagement decisions are needed. However,for the purposes of dredged materialdisposal, sediment at this level cannot bedisposed of in an area where existingsediment concentrations are below the NoEffect Level.

8

3. If the sediment concentration exceeds theLowest Effect Level, then the concentration iscompared with the local background values forthat parameter. Background values can bederived from physically contiguous areas thatare unaffected by point-source discharges, orif these do not exist, then from the"pre-colonial" sediment horizon. The latterwould represent background levels in existencebefore European colonization of the area and isgenerally considered as the area below theAmbrosia pollen horizon. In those instanceswhere local values are not available, theconcentration may be compared to thebackground values listed in Tables 4 and 5.These are based on values from the GreatLakes and may not be applicable to inlandsites.

3a. If the sediment concentration is below thenatural background then no furthermanagement decisions need to be considered.

3b. If the sediment concentration also exceeds thelocal background value, then the next step isto determine whether the sediment poses athreat to aquatic life, and if so, the severity ofthis effect. Since the range of sedimentconcentrations that falls between the LowestEffect Level and the Severe Effect Level is inmost cases very large, it is necessary todistinguish between situations where aparameter may exceed the Lowest Effect Levelonly slightly, from one where the levels areclose to the Severe Effect Level. The biologicaleffects in such cases would be expected todiffer widely. A number of biologicalassessment techniques would be expected tobe used in such an assessment. These shouldencompass laboratory and field-basedmeasures on both individual toxic effects aswell as "ecosystem" measures. The types andcomplexity of analyses will differ according tothe specific characteristics (sediment type,contaminant) of each site.

3c. Assessment of the biological effects in turnpermits management decisions to be made onthe need and potential effectiveness of theavailable remedial options including sourcecontrol and sediment remediation. This stepwill include consideration of the environmentaleffects and will also incorporate the socio-economic impacts of both the sedimentcontamination and the remedial options. Thisstep would be expected to proceed in mostcases with considerable public involvement.

3d. The final choices made would involve source.

control and either the implementation ofremedial action or a decision to leave andmonitor. The basis for choosing the lattermay be a lack of environmental effects ormay be based on socio-economicconsiderations. In some situations leavingcontaminated material in place is also anaccepted and effective remedial option andmay be less environmentally damaging.Where biological effects were found to bepresent but a decision has been made toleave the material in place, or where this isthe accepted remedial action, monitoringmay be required along with consideration ofother actions that may be needed to restrictpublic exposure.

4. If the concentration of the contaminant inthe sediment exceeds the Severe Effect Levelthen the sediment bioassay described insection 3.2.3, designed to assess whetherthe sediment is acutely toxic, is required.

4a. If on the basis of these tests the sedimenthas not been found to be acutely toxic, thenthe assessment procedure as described insteps 3b through 3d above are to befollowed.

4b. Where the sediment has been found to beacutely toxic on the basis of the bioassaytests, it is necessary to evaluate sourcecontrol and all remedial options, includingleaving the material in place. In some cases,management decisions may involve theimplementation of interim remedial action.

In areas where contaminants in sediment areat or above the Severe Effect Level, the sedimentis deemed to be highly contaminated andmeasures in addition to source control may berequired to dean up the sediment. Such measuresshould be determined on the basis of the biologicaltests outlined below. If the sediment fails either ofthe tests, in situ remedial action is warranted. Ifthe sediment passes both tests, efforts should bedirected towards point and non-point sourcecontrol. In situ clean-up must not be a substitutefor source control. The sediment evaluationprocedure is outlined in Figure 2.

Biological Tests

The following acute lethality test, or anequivalent test approved by MOE, will be carriedout to determine the need for in situ sedimentremedial action. Details on the following tests areprovided in Bedard et al. (1992).

9

Sediment Bioassay Protocol

The experiments are run as staticwhole-sediment beaker tests, using two types ofaquatic biota: 3-4 month old fathead minnows,Pimephales promelas (to assess effects ofcontaminated sediment on water columnorganisms) and 3-4 month old reared nymphs ofthe burrowing mayfly, Hexagenia limbata (toassess effects of contaminated sediment on asediment-dwelling organism). The organisms areplaced in jars (2 litre) with dechlorinated waterand sediment (4:1 ratio) for a 10-day exposureperiod. At the end of the experiment, percentmortality is calculated.

Selection of Controls

Controls are very important and necessaryfor proper interpretation of bioassay results. Twotypes of control sediments are selected for theSediment Bioassay Protocol and these are:

- Sediments in which test organismsare cultured.

- Control site from study location,upstream or removed from thepollution sources being assessed butas similar as possible in composition.

Data Interpretation

Data interpretation involves comparingbioassay results from test sediments to resultsfrom:

- replicate test sediments to addressvariability among replicates

- control sediments that organismswere cultured in

- upstream control sediments orsediments removed from pollutionsources being assessed.

Statistically significant (P <0.05) differencesbetween test and control sediments for thevarious endpoints indicate that test sedimentshave negatively impacted the biota. Controlmortality is monitored and must not exceed 15%for the validation of test results.

3.2.3 Dredged Material Disposal Dredged material refers to any material removedfrom the bottom of a watercourse as a result ofcapital or maintenance dredging, remedial actionor spills clean-up. The conditions outlined below

relate only to material being considered fordisposal in open water and does not includematerial to be placed within Confined DisposalFacilities (CDFs). Analyses will be performed forall parameters listed in Tables 1 and 2, unlessprevious data suggest the -absence of certainparameters. In addition, chemical analysis may berequired for some or all of the parameters inTable 3.

A. Disposal in Areas With Sediment QualityEqual to or Better Than the No Effect LevelGuidelines.The dredged material to be disposed ofmust not exceed the No Effect LevelGuidelines.

B. Disposal in Areas With Sediment QualityExceeding the No Effect Level Guidelines.

The dredged material to be disposed of insuch areas must be below the Lowest Effect LevelGuidelines, subject to the conditions described in3.1.1.(g). Detailed application of these guidelinesis described below and is shown in Figure 3.

Sediment Evaluation for Dredged MaterialDisposal

Dredge material disposal in open waterrequires that both the material to be removed aswell as the material in the `disposal area beanalyzed. Each parameter is compared to thePSQG levels. In practice, the material is matchedto the disposal area, which in turn will beclassified into one of three groups.

Group 1

1a. The concentrations of contaminants insediments in the disposal area are below theNo Effect Level. If the concentrations in thedredged material are also below the NoEffect Level the material is suitable fordisposal at this site.

1b. If the concentrations in the dredgedsediments are above the No Effect Levelthen this material is not suitable for disposalat this site, since this would result incontamination of a dean site with sedimentof a lesser quality. However, if theconcentrations in the dredged material arebelow the Lowest Effect Level, it may besuitable for disposal at another site whereexisting sediment concentrations are abovethe No Effect Level.

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1c. Material that exceeds the Lowest EffectLevel for any parameter is not suitable foropen water disposal at this site.

Group 2

2a. The sediments in the disposal area areabove the No Effect Level but still below theLowest Effect Level. If the concentrations inthe dredged material are below the NoEffect Level then the material is suitable foropen water disposal at this site.

2b. Similarly, if the dredged material is abovethe No Effect Level but below the LowestEffect Level, the material is also suitable fordisposal at this site. Material that exceedsthe Lowest Effect Level is not suitable foropen water disposal at this site.

Group 33a. If the sediments in the disposal area are

contaminated to above the Lowest EffectLevel, material that is below the LowestEffect Level is suitable for open waterdisposal at this site.

3b. Material that exceeds the Lowest EffectLevel for organic compounds and mercury isnot suitable for open water disposal.Material that exceeds the Lowest EffectLevel for metals other than mercury issuitable for open water disposal undercertain conditions. If the material is at orbelow the Great Lakes background (asdefined in Table 4) and does not exceedambient sediment levels then the material issuitable for open water disposal at this site.

3.2.4 Spills Clean-up

In areas where ambient or backgroundsediment levels of the substance(s) spilled arebelow the No Effect Level, the clean-up level will,as a minimum, be to the No Effect Level. If theambient sediment levels for that watercourse areabove the No Effect Level, then cleanup will be, asa minimum, to the local ambient level. To cleanup beyond the ambient level would be of nolasting benefit due to the long-term migration andcycling of sediment within the ecosystem.

SECTION 4

PROTOCOL FOR SETTING SEDIMENTQUALITY GUIDELINES

4.1 RATIONALE FOR SETTING SEDIMENTQUALITY GUIDELINES

In developing guidelines to provide adequateprotection for biological resources, the Ministry hasattempted to ensure that the methods employedconsider the full range of natural processesgoverning the fate and distribution of contaminantsin the natural environment. Since benthicorganisms respond to a variety of stress-inducingfactors they are, in essence, integrators of all thephysical, chemical and biological phenomena beingexperienced in their environment and theseorganisms should form the basis of any methodused in setting sediment guidelines.

Because individual species may responddifferently to stress-inducing factors it is verydifficult to study a specific organism (eg. asensitive species) with the hope of developingguidelines that will protect the rest of thecommunity. Sensitivity to chemical contaminantshas not been fully evaluated for different benthicorganisms and most sediment bioassay work hasbeen concerned mainly with a few selected species(eg. the mayfly Hexagenia). While the mayfly hastraditionally been used as a "sensitive indicatororganism for factors such as low dissolved oxygen,its sensitivity relative to other benthic organismshas not been dearly established for chemicalcontaminants. Therefore, in developing PSQGs, theMinistry has not relied on single-species data.

Similarly, a method that relies heavily onthose species that are known to be extremelytolerant of contaminants in sediment cannot resultin guidelines that will adequately protect lesstolerant members of the aquatic community. It hasbeen demonstrated that some populations canadapt to varying levels of environmentalcontamination with increasing tolerance to thesecontaminants occurring in succeeding generations.This can present difficulty in laboratory studies ofreared populations since these may lack thegenetic diversity found in natural populations andresponses may not be consistent with thoseobservable under field conditions.

Another concern in relation to placing heavyreliance on laboratory data stems from the factthat in most situations contaminants in sedimentsexist as mixtures of various substances. Laboratorytests have been geared towards examining theeffects of single substances and laboratory datacan be difficult to apply to field situations.

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In developing the protocol for settingSediment Quality Guidelines, the ministryconsidered a number of different approachesdeveloped by state and federal agencies in NorthAmerica that employed various degrees ofbiological assessment. The various suggestions forthe development of Sediment Quality Guidelinescan be summarized in five approaches as possiblemeans of setting sediment quality guidelines. Atpresent, no single approach can adequatelyaccount for all the factors that operate in naturalsediments and each of the five approaches haspositive attributes as well as limitations with regardto the development of biologically basedguidelines. The rationale used in setting SedimentQuality Guidelines includes a number ofconsiderations which are detailed below. Theseconsiderations provided the basis for selecting thebest method or combination of methods forSediment Quality Development.

1. Sediment Quality Guidelines should considera range of contaminant concentrations that iswide enough to determine the level at whichecotoxic effects become noticeable. This canbe achieved most effectively by looking at alarge number of organisms under the widestpossible range of contaminant exposure. Onlythen can the appropriate ecotoxic level beadequately determined. A restricted rangemay result in the setting of guidelines that arenot reflective of actual ecotoxic effects onorganisms and as such may beoverprotective. This is especially importantwhere the range of effects used may notcover the entire tolerance range of the speciesin question.

2. PSQGs should be based on cause-effectrelationships between a specific contaminantand benthic organisms since it is necessary todemonstrate that at a certain concentration acontaminant results in adverse effects onbenthic organisms.

3. PSQGs should account for contaminant effectsin a multi-contaminant medium. Sincecontaminated sediments usually consist ofmixtures of substances, the presence of anumber of different contaminants, any or allof which may affect the response of theorganisms to the contaminant beinginvestigated must be considered. Sincecombinations of contaminants may evokedifferent responses than those occurringsingly (through either synergistic or

antagonistic effects) these effects must beaccounted for as well. A PSQG method mustincorporate this feature into the derivation ofa number for specific contaminants.

4. PSQGs should consider chronic effects ofcontaminants on aquatic biota since these canaffect the long term viability of aquaticorganism populations. Methods that consideronly acute effects do not offer adequateprotection, since sediment concentrationsreflect long-term conditions and are notsubject to the extreme temporal variability ofwater column contaminant concentrations.

5. The PSQGs should be capable of incorporatingand accounting for the range of environmentalfactors that could have a bearing on thepresence or absence of organisms in a givenarea. Contaminant behaviour and organisms'well-being are governed by a variety ofnatural physical, chemical and biologicalprocesses. If these processes are notaccounted for in a PSQG method then theresulting guidelines will be unrealistic. Forexample, organisms may be absent from agiven area not because of the level ofcontaminants but because of unsuitablehabitat, low dissolved oxygen, or interspecificcompetition. In formulating a guideline it isessential that these factors be consideredalong with the chemical data. If they are notconsidered, the numerical value obtainedwould not necessarily be protective of aquaticspecies. This will also reduce the need forsite-specific guidelines, since a full range ofenvironmental conditions will have beencovered.

4.2 APPROACHES TO SEDIMENT QUALITYGUIDELINE DEVELOPMENT.

As part of the sediment guideline developmentprocess, the Ministry has carried out an extensiveliterature review of possible approaches to thedevelopment of sediment guidelines. This efforthas resulted in the selection of five potentialapproaches for this purpose. These are:

1. Sediment Background Approach2. Equilibrium Partitioning Approach

(Water - Sediment and Biota - Water -Sediment Partitioning)

3. Apparent Effects Threshold Approach4. Screening Level Concentration Approach5. Spiked Bioassay Approach

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The five approaches are discussed below andadditional details can be found in the pertinentliterature cited for each method.

4.2.1 Sediment Background Approach

In the Background Approach, sedimentcontaminant concentrations are compared toconcentrations from reference background siteswhere contaminant levels are deemed to beacceptable (OMOE 1987, 1988). Using theBackground Approach, levels are set according toa "suitable" reference site or "acceptable" level ofcontamination. A suitable reference site may beone where sediments are deemed to be relativelyunaffected by anthropogenic inputs. Alternativelya suitable reference site may be derived throughsediment profiles. In the latter, the pre-industrialsediment horizon, as determined throughtechniques such as palynology, could be used todetermine background levels.

The basis of the Background method is theimplicit assumption that concentrations abovethese background values have an adverse effecton aquatic organisms.

For the purposes of PSQG development a"pre-industrial" standard could be adopted onlyfor metals. The strictly anthropogenic (man-made) organic contaminants, for which back-ground levels should theoretically be zero, wouldrequire adoption of a contemporary surficialsediment standard, based on a suitable referencesite.

Advantages:

The data requirements of the BackgroundApproach are minimal in that the method requiresonly measurement of the chemical concentrationsof contaminants in sediments. As such it can beused with the existing data, thus minimizing theneed for additional data collection.

The method does not require quantitativetoxicological data and avoids the need to seekmechanistic chemical explanations forcontaminant behaviour or biological effects.

Background limits have advantages from anenforcement perspective since the BackgroundApproach does provide an indication of thechemical concentration for metals that is expectedto occur naturally. While it is possible that

biological effects may occur in some species atmetal concentrations indistinguishable from non-anthropogenic background, it is difficult to justifyenforcement of a standard that has never beenrealized in nature. Thus background levels formetals can provide a practical lower limit formanagement decisions. For organic contaminants,which are largely anthropogenic, backgroundshould theoretically be zero. In most areas,however, contaminants have found their way intosediment and a contemporary benchmark basedon current average concentrations for a suitablereference area may provide the practical lowerlimit for enforcement.

There is at present an adequate database fordeveloping sediment guidelines for severalcontaminants using the Background Approach.

Limitations:

Since the Background Approach relies only onthe chemical concentration of contaminants insediments it has no biological basis. Becausebiological effects data are not considered,cause-effect relationships between sedimentcontaminant levels and sediment-dwellingorganisms cannot be determined.

The exclusive use of chemical data impliesthat sediment characteristics have no influence onthe resultant biological effects, but rather thatchemical concentrations alone are responsible forthe observed effects. However, sedimentcharacteristics (i.e., grain size, organic content,dissolved oxygen levels) have been shown to bemajor factors affecting benthic communitycomposition.

Implicit in the method is the assumption thatthe chemicals present are in their biologicallyavailable forms. The method therefore, makes noallowance for the occurrence of different chemicalspecies with differing biological availability andtoxicity.

A further limitation of this approach is thatbackground levels tend to be highly site-specific.They therefore require the designation of areference site, which itself is likely to be highlysubjective.

4,2.2 Equilibrium Partitioning Approaches

Phase partitioning of organic compounds has

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been used to describe the distribution of certainorganic compounds in aquatic compartments.Partitioning, like adsorption, is one of theprocesses by which organic compounds can besorbed to sediments. A major difference however,is that partitioning is solubility dependent andtherefore, reversible (i.e. equilibrium) partitioningof non-polar organic compounds is a function oftheir solubility in water. The very insolublecompounds, as a result, partition strongly tosediment with only very minor amounts in water.These compounds tend to have high partitioncoefficients, as measured by the octanol-waterpartition coefficient, KOW. The KOW is the ratio ofthe amount of the compound that is soluble in anorganic solvent such as octanol relative to theamount soluble in water.

The partitioning approaches have beenextensively investigated by the U.S. EPA (Pavlou& Weston 1984). A basic assumption of thisapproach is that the distribution of contaminantsamong different compartments in sediment iscontrolled in a predictable manner by acontinuous equilibrium exchange among sedimentsolids and the interstitial water. Partitioning tothese two phases can therefore be calculated bythe quantity of sorbent in the sediment, for whichorganic carbon is the primary sorbent, and thepartition coefficient KOC. KOC values, which can beestimated from KOW, are normalized to sedimentorganic content.

The EP approaches also assume thatinterstitial water is the primary route of organismexposure to contaminants in sediments.Therefore, this approach assumes that only theamount of contaminant partitioning to the wateris of interest, the amounts partitioning to thesediments being considered as unavailable.

Using this approach, contaminant-specificpartition coefficients are determined (generallyexpressed in terms of organic carbon content ofsediment) and used to predict the distribution ofthe contaminant between sediment and interstitialwater. It must be pointed out that this approachcan only be used for contaminants that partitionbetween environmental phases. Contaminantsthat do not partition appreciably into sedimentorganic matter, and those whose chemicalbehaviour is highly unpredictable, such as themetals, cannot be considered using thepartitioning approach.

Under the EP approach, a generic (i.e.

equally applicable to all sites) organiccarbon-normalized partition coefficient KOC isdeveloped and is then multiplied by an existingPWQO/G to derive a sediment guideline. Inessence, the distribution coefficients for thenon-polar organics are used to establish thechemical concentration in the sediments that, atequilibrium, will not exceed PWQO/Gs in theinterstitial water.

Sediment Quality Guidelines based on theequilibrium partitioning of organics can becalculated in a number of ways, depending on thetype of data available.

1. Water - Sediment Equilibrium PartitioningApproach

The water - sediment partitioning approachis a generic partitioning method which derives asediment quality guideline from the partitioning ofa chemical to the water and the sediment solidphases. There is sufficient evidence to show thatsediment organic carbon is the primaryenvironmental factor influencing partitioning (DiToro et al. 1985 in OMOE 1988) the partitioncoefficient, Kd, is normalized for organic contentand an organic carbon-normalized sediment-waterpartition coefficient is derived (KOC). This caneither be derived empirically, or calculated fromthe octanolwater partition coefficient. Thepartition coefficient is then multiplied by a waterquality criterion (such as a PWQO) to derive asediment quality guideline.

2. Biota - Water - Sediment Equilibrium Part-itioning Approach

The Biota - Water - Sediment PartitioningApproach is a generic partitioning method whichderives a sediment guideline from an existingtissue residue criterion. It is a two step approachutilizing a generic water - biota bioconcentrationfactor (BCF) to relate the tissue criterion to acorresponding water concentration. Forbioaccumulable substances this relationshipdetermines the tissue-water concentration level(TWCL). The TWCL is the value that must not beexceeded in water in order to prevent exceedanceof the tissue residue criteria from which the TWCLwas derived. The TWCL, therefore, is equivalent toa water-quality criterion. Following this step theapproach is similar to that described for the water- sediment approach with the TWCL used in placeof the water quality criterion.

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Advantages:

Generic Partitioning Approaches arebiologically based to the extent that existing wateror tissue criteria are biologically based and,therefore, provide more defensible guidelines thanthe Background Approach. Since they make use ofthe virtual no-effect levels determined fromexisting Provincial Water Quality Objectives andGuidelines (PWQO/Gs) the sediment guidelinesderived through generic partitioning approachescan be considered no-effect levels for theprotection of those end-uses the water qualityguidelines were designed to achieve.

The partitioning approach relies on an existingtoxicological rationale which has been establishedduring the development of the water qualitycriterion being used. Thus, a new toxicologicalevaluation is not required provided that the waterquality criterion has been derived to protect thosebenthic organisms which are exposed to theinterstitial water. However, a correspondinglimitation to the approach is its applicability only tochemicals which have water quality criteria.Moreover, if the water and sediment criteria aremeant to protect different organisms then anassumption is made that the two sets of organismsare of equal sensitivity to given levels ofcontaminants.

Limitations:

The basic assumption that availability of anorganic compound to aquatic organisms iscontrolled by the amounts partitioning to the waterignores both the sediments and food chain effectsas potential sources. It has not yet been proventhat the interstitial water is the only significantroute of exposure and for the highly hydrophobiccompounds (those with high KOW), all of thesesources may be significant routes of exposure.

Tissue residue criteria are generally based onhuman health considerations and human foodconsumption patterns. Therefore, the tissueresidue criteria apply to human food organismssuch as fish, rather than benthic organisms.Similarly, the BCF applies to fish, and the waterconcentration (TWCL) thus derived applies to thewater column in which the fish lives. This approachis limited by the substantial gap that existsbetween the water column compartment and theinterstitial water compartment that is assumed tobe in equilibrium with the sediments.

The reduction in contaminant concentration

from the interstitial water the water columncompartment is likely to be highly site-specificdepending on local-circulation.

Current use of the Partitioning Approach islimited to those contaminants that exhibitpredictable partitioning behaviour. Since thepartitioning of metals in sediments is highlyunpredictable (e.g., sediment-water partitioncoefficients for metals can span a wide range ofvalues differing by orders of magnitude dependingon such factors as redox potential, pH, dissolvedoxygen and organic matter content of the sediment)and polar organics generally do not partition intosediment, the partitioning approaches areconsidered applicable only to non-polar organiccompounds.

The scientific validity of a sediment guidelineobtained through the partitioning approaches reliesheavily on the accuracy of the partitioningcoefficients (Kd) used. The published values forpartition coefficients obtained by different authorscan differ by an order of magnitude. This presentsgreat difficulty in choosing a representative valuefor use in guideline development work and unless astandard approach is used it will be difficult toobtain consistent or compatible guidelines using theEP approach.

At present the EP approach cannot account forall the forms a contaminant can exist in and all thepossible sediment constituents it can partition to.This is currently a drawback to the EP approachsince the various forms of a contaminant have theirown toxicity and partitioning characteristics. Severalspecies of a contaminant may be bioavailable andtoxic, but often their concentrations are more orless linearly dependent on the concentration of asingle species. While it has been possible toestablish that one species correlates with theobserved toxic effects for the non-polar organics,this has not been possible for the metals or thepolar organics. The partitioning approach does notwork for metals or polar organics due to themultiplicity of adsorption mechanisms theseundergo. It is not even clear which sedimentcomponents are controlling partitioning.

4.23 Apparent Effects Threshold Approach (AET)

The AET, as developed by Tetra Tech (1986) isa statistically based approach that attempts toestablish quantitative relationships betweenindividual sediment contaminants and observedbiological effects. The biological effects can be both

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field measured effects such as changes in benthiccommunity structure and laboratory measuredeffects through the use of sediment bioassays.The basis of this technique is to find the sedimentconcentration of a contaminant above whichsignificant biological effects are always observed.These effects can be any or all of a number ofdifferent types, such as chronic or acute toxicity,changes in community composition, andbioaccumulation and are considered in conjunctionwith the measured sediment contaminant levels.Inherent in the approach is the assumption thatobserved effects above this level of contaminationare specifically related to the contaminant ofinterest, while below this level any effectsobserved could be due to other contaminants.

Advantages:

The AET Approach is effects based andtherefore more defensible than the partitioningapproaches in relation to the protection of benthicorganisms. The method assumes a directcause-effect relationship between sedimentconcentrations of a contaminant and theoccurrence of significant biological effects.

Unlike the partitioning approach the AETmakes no assumptions regarding contaminantavailability from the various environmentalcompartments. Therefore the effects on biota canbe due to contaminants available through bothadsorption from sediments and interstitial waterand through absorption from ingested matter.

Limitations:

The method is unable to separate thebiological effects that may be due to acombination of contaminants.

While assuming a cause-effect relationship,the method cannot dearly demonstrate acause-effect relationship for any singlecontaminant. Thus, while definite ecotoxic effectscan be established, these cannot be attributed toany one chemical contaminant.

In using the AET approach care must beexercised in selecting the species of organism tobe used and the particular type of effects(endpoints) to be considered. If the data usedconsist of mixed species and endpoints, the leastsensitive of these, will always predominate andthe guidelines derived may not protect other moresensitive species. For example, if the data base

for a particular contaminant contains data on acutetoxicity to tubificid oligochaetes, then the AET willbe designed to protect against acute toxicity totubificids. It will not protect species that are moresensitive nor will it provide protection againstchronic effects.

For most practical purposes this methodrequires chronic toxicity data since results from theexisting database indicate guidelines tend to behigher than those calculated by other means, insome cases by an order of magnitude. This isusually due to the use of acute toxicity data whichneeds a correction factor to adjust to chronictoxicity. The development of a chronic toxicitydatabase (i.e, one based on reproductive effectsand effects on the most sensitive life stages) itselfrequires a very extensive set of information whichat present does not exist in a standardized form. Inorder to obtain such information, considerablelaboratory testing will have to be carried out.In-addition, for data from different investigators tobe useful, consistency in procedures and definitionof endpoints will be necessary. To this end, resultsfrom single investigators are the most effective forattaining consistent results:

In practice, guidelines generated by the AETapproach are likely to be underprotective since thismethod determines the contaminant level abovewhich biological effects are always expected.Biological effects, however, can be and areobserved at chemical concentrations lower thanthese values, though these effects may not occurin all samples.

The AET method is applicable for all types ofcontaminants, making use of both laboratory testson sediments (spiked sediments) and field data. Inlaboratory tests, of field-collected sediments it maynot be possible, to separate the effects of mixturesof chemicals. If spiked sediments are used, onlysingle contaminant or known (specific) mixturescan be used and therefore this method suffers fromsome of the same limitations as the SpikedBioassay method (discussed below). In using fieldcollected sediments in conjunction with other fielddata (e.g. community composition), it is notpossible to separate the effects of mixtures ofcontaminants and this method suffers from thelimitations affecting the SLC method.

4.2.4 The Screening Level ConcentrationApproach (SLC)

The SLC, like the AET, is an effects based

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approach applicable mainly to benthic organisms.The SLC approach uses field data on theco-occurrence in sediments of benthic infaunalspecies and different concentrations ofcontaminants. The SLC is an estimate of the highestconcentration of a contaminant that can betolerated by a specific proportion of benthic species.In its original derivation and application, the 95th

percentile was used.

The SLC, as developed by Neff et al (1986), iscalculated through a two step process. First, for alarge number of species (at least ten for eachchemical) a species SLC (SSLC) is calculated byplotting the frequency distribution of thecontaminant concentrations over all sites (at leastten) where the species is present. The 90th

percentile of this distribution is then taken as theSSLC for that species. The 90th percentile waschosen to provide a more conservative estimate ofthe SSLC. Extreme sediment concentrations may bean aspect of specific sediment characteristicsresulting in low biological availability relative to thesediment concentration. By choosing the 90th

percentile, these values are excluded. In the secondstep, the SSLCs for each species are plotted as afrequency distribution and the 5th percentile isinterpolated from this distribution. This is the SLCand represents the concentration which 95% of thespecies can tolerate.

A basic assumption in the method is that thedata cover the full tolerance range of each species.This assumption requires that a large range ofchemical concentrations be sampled in each case(at least two orders of magnitude) since an SLC willbe generated whether or not this assumption istrue. This is important though sometimes difficult toverify. The difficulty lies in the fact that the fulltolerance range of most species is not known.

Sediment contaminant concentrations for thenon-polar organics are normalized to TOC contentof the sediments. Since these compounds generallypartition strongly to organic matter, the normalizedconcentration should more closely representcontaminant availability to benthic organisms. Formetals and polar organics, bulk sedimentconcentrations are used since the bestnormalization procedures for representation ofmetal availability are as yet unresolved.

Advantages:

Since the SLC approach does not make anyassumptions about the absence of a species and considers only those species present, the SLC

approach does not require a priori assumptionsconcerning cause-effect relationships betweensediment contaminant concentrations and thepresence or absence of benthic species. As norelationship is assumed it is not necessary to takeinto account the wide variety of environmentalfactors that affect benthic communities, such assubstrate type, temperature and depth.

However, valid a posteriori inferences can bedrawn from this type of analysis regarding therange of sediment contaminant concentrations thatcan be tolerated by the sediment infauna sincefield data on the co-occurrence of benthic infaunalspecies and sediment contaminant concentrationsare used.

However, since the SLC Approach uses fielddata on the co-occurrence in the field ofcontaminants and benthic species, theenvironmental factors acting on the speciesdistribution are already integrated into the data-setand the response determined is a measure of boththe environmental factors and the contaminantlevels. It also integrates changes in chronicresponses such as reproduction/ fecundity andsensitive life-stages, since it is a cumulativemeasure of effects. In addition, it integrates intothe biological response any synergistic or additiveeffects from multiple contaminants as they wouldoccur in natural sediments. Because of this, theSLC approach overcomes the difficulties of applyingbioassay data to field situations, and the lack ofuncertainty associated with partition coefficients.

While it was originally developed primarily foruse with non-polar organics (using TOC normal-ization) it is also appropriate for metals and polarorganics as well since it can be used with orwithout TOC normalization.

At present the size of the database hasdetermined that the SLC level be set at the 5thpercentile of the SLC frequency distribution.However, as the database continues to expand itshould be possible to reliably calculate the 1stpercentile (i.e. the level of a contaminant that 99%of the species present can tolerate). The precisionof the SLC is directly related to the size of thedatabase and the range of variability of the variousfactors within the database. Therefore great caremust be taken to include data taken over the fullrange of conditions since a database skewed toeither lightly or heavily contaminated areas willyield guidelines that are either too conservative(overprotective) or do not provide adequateprotection for aquatic life (underprotective).

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Limitations:

The major limitation of the SLC approach isthe difficulty in determining a direct cause-effectrelationship between any one contaminant andthe benthic biota, since very rarely is a singlecontaminant present in natural situations.Therefore, the effects observed are related to theentire mixture of chemicals.

The range and distribution of contaminantconcentrations and the particular species used togenerate them can significantly affect thecalculation of the SLC value. The use of only lowvalues of contaminant concentration may notencompass the entire tolerance range of thespecies and the concentration would be below thelevel that would adversely affect the distributionof that species. In such situations, an SLC wouldstill be generated but the value would beconservative and unrealistic. This can beovercome by ensuring that the database includevalues from heavily contaminated areas.

The SLC is also sensitive to the species usedin the database. Unlike the Partitioning approach,the SLC does not make any assumptionsregarding the possible routes of effect fromaquatic contaminants, all possible modes ofexposure are taken into account. Sincecontaminant availability from the sediments maydiffer in relation to the feeding habits of theorganisms used, the proportion of species fromeach of the feeding groups will determine theshape of the SLC curve. This can also beovercome by limiting the database to thoseorganisms living in or feeding on the sediment.

4.2.5 Spiked Bioassay Approach

In this approach, dose-response relationshipsare determined by exposing test organisms, undercontrolled laboratory conditions, to sediments thathave been spiked with known amounts ofcontaminants (OMOE 1987, 1988). Sedimentquality guideline values can then be determinedusing the sediment bioassay data in a mannersimilar to that in which aqueous bioassays areused to establish water quality criteria. Wherechronic toxicity data are not available, anapproximation can be obtained by using acutetoxicity endpoints that have been adjusteddownwards by a factor of ten to obtain a chronicprotection level and then applying a suitablesafety factor.

Advantages:

The major advantage of this approach is thata direct cause-effect relationship can bedetermined, at least under laboratory conditions,for a specific chemical or combination of chemicalsfor any species of organism.

Limitations:

Despite this advantage, limitations exist that,at present, preclude the use of this method forsetting guidelines. Techniques have not beenstandardized for spiking sediments and differencesin methods/techniques can strongly influence theresults. In addition, laboratory bioassaysperformed under controlled conditions may not bedirectly applicable to field situations whereconditions may vary considerably from thoseencountered in the laboratory. In order to deriverealistic guidelines from the Bioassay Approachefforts will have to be made to test differentsediments with various chemical mixtures indiffering proportions and using differentorganisms, as would exist in field situations.

4.3 Summary Evaluations of the VariousApproaches to PSQG Development

As pointed out earlier, the major objectivesin the development of sediment quality guidelinesare to provide protection to aquatic organisms andensure water quality protection, as well asguidance in decision-making related to abatementefforts and remedial action. As such they areintended to be both proactive and reactive inapplication. The primary basis for such decisionsis the protection of biological resources againstthe lethal and sublethal effects of contaminatedsediment.

The biological resources that could potentiallybe impacted by, contaminants in sediment span awide range. These include organisms that couldbe impacted directly, namely the benthic speciesthat live in or feed on the sediment, and watercolumn organisms that could sorb contaminantsreleased from the sediment to water and/orthrough the consumption of benthic organisms;and those impacted indirectly such as non-aquaticconsumers (humans and wildlife) of top aquaticpredators such as fish.

In reviewing the five approaches to settingsediment guidelines, it is apparent that each

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approach has certain merits as well as limitations.

The Background Approach while larking abiological basis, does provide a good indication ofthe levels at which metals are expected to occurnaturally and thus provides a realistic lower limitfor guideline development.

The partitioning approaches to sedimentguideline development use existing criteria suchas a water quality or tissue residue criteria whichcan be considered as virtual no-effect values. Theresulting sediment guidelines can therefore alsobe considered as virtual no-effect values for theprotection of water column organisms fromsediment-bound contaminants.

The partitioning approach is attractivebecause it is capable of providing a measure ofcontaminant availability from sediments with aminimum of data. Due to the incorporation ofvarious safety factors in the generation of PWQOs,this approach is able to provide an estimate of theno-effect level of a contaminant in sediments.How protective this value may be depends on thesediment organisms, the size of the safety factor,and the type of sediment. The approach is limitedby its assumption of a single route of exposure foraquatic organisms and its restriction to thenon-polar organics.

The AET approach appears best suited todiscriminating between contaminated anduncontaminated areas within a site, since the dataused tend to be highly site specific. As a result,any guidelines derived will also be site-specific.The major limitation lies in the assumption of acause-effect relationship that the methods provesunable to demonstrate. There is also a paucity ofchronic effects data suitable for AET applications,particularly if consistency in level of protection(i.e. single species and endpoint) is desired.Therefore, the AET approach is judged lessacceptable than the other effects-basedapproaches.

The SLC approach has an advantage in thatno cause-effect relationships are assumed andtherefore, it does not need to account for all ofthe natural environmental factors that can affectorganisms. The effects of these are alreadyintegrated into the data. The effects ofmulti-contaminant interactions are also factoredinto the data set used in the calculations and, witha sufficiently large database, the effects of othercontaminants can be minimized The SLC approachwould be less defensible on a theoretical basisthan the Spiked Bioassay Approach if the data

bases for the two approaches were comparable. Ithas been found, however, that relevantinformation from bioassays is considerablylacking, especially in relation to the impacts ofchemical mixtures on benthic populations. Due tothe paucity of Spiked Bioassay data, it is difficultto achieve consistency in the level of protection(i.e. a variety of species and endpoints must beconsidered). The problem could be rectified withfurther chronic data acquisition, particularly ifstandard spiking techniques were adopted. Inpractice, the methodology has not beenstandardized and variations in experimentalprotocol can greatly influence the results. Theability to transpose laboratory derived results tonatural situations is also questionable.

Since there is presently a significant lack ofadequate data for use in the development ofsediment quality guidelines using the spikedbioassay approach, the SLC approach offers thebest means of developing sediment qualityguidelines for the protection of the benthiccommunity. This is especially true since therealready exists a good database for the GreatLakes Region.

In accordance with the merits and limitationsof the various approaches to sediment guidelinedevelopment, their use can be summarized asfollows:

- Partitioning approaches have been usedto develop virtual no-effect levels for theprotection of water quality and uses, andhealth risks associated with humans andwildlife through the consumption of fish.These can be used to set sedimentcontaminant levels that are alsoprotective of these same uses.

- The effects-based approaches (AET, SLCand Bioassay) are being used to developguidelines for the protection of benthicorganisms. Based on the existinginformation base, only the SLC approachis of immediate use in the developmentof sediment quality guidelines.

- The Background Approach has been usedto establish levels where adequate datado not exist for application of any of theother methods or where the methodsused are inappropriate for the type ofcompound. In addition, backgroundlevels provide a practical lower limit formanagement decisions.

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As sediment bioassay techniques are refinedand standardized it may be necessary to revisethe protocol to accommodate these techniques aswell, though it is unlikely that these will eversupplant field based approaches such as the SLC,since some field verification of laboratory resultswill always be necessary.

4.4 CALCULATION OF SEDIMENT QUALITYGUIDELINES

The calculation of specific guideline values forthe three levels of guidelines referred to in Section2 are described in detail below.

4.4.1 THE NO EFFECT LEVEL

Since this is intended as the level at whichcontaminants in sediments do not present a threatto water quality and uses, benthic biota, wildlife orhuman health, the parameter values used inderiving the No Effect Levels must be the moststringent criteria.

The No Effect Level is principally designed toprotect against biomagnification through the foodchain. Since these effects are most often observedwith the nonpolar organics, this guideline level isnot applicable to most of the trace metals.

The partitioning approaches are used to setthese guidelines since, with appropriate safetyfactors PWQOs/Gs are designed to protect againstbiomagnification of contaminants through the foodchain, as well as all water quality uses andorganisms.

At present, reliable partition coefficients canonly be derived for the nonpolar organics, sinceonly these compounds undergo predictablepartitioning behaviour in sediments. No EffectLevel Guidelines cannot be calculated for metalsand polar organics.

Non-Polar Organics

The No Effect Level for non-polar organics isobtained through a chemical equilibriumpartitioning approach using PWQOs.

The calculations for each criterion are asfollows:

A PWQO/G value is multiplied by an organiccarbon-normalized sediment-water partitioncoefficient, KOC. Normalization was recommendedby Pavlou and Weston (1984) and OMOE (1988)since sediment organic carbon has been found tobe the primary environmental factor influencingpartitioning.

A PSQG is then derived through theequation:

SQG = KOC x PWQO/G

where PSQG is the sediment quality guidelinenormalized to the sediment organic carboncontent (TOC). This is converted to a bulksediment basis by assuming a 1% TOCconcentration. A 1% level for sedimentorganic carbon is used for converting to abulk sediment basis, since calculations usingthe SLC approach have shown that this is thelowest effect level of organic carbon in thesediment. A bulk sediment calculation basedon the actual organic carbon content of thesediment has been avoided for this reason.

The organic carbon-normalized partitioncoefficient is calculated from either anexperimentally derived sediment-water partitioncoefficient:

Ksed = ([X]sed / O.C.) / [X]IW

where

[X]sed is the concentration of compound X inthe sediment (as mass of X/mass oforganic carbon) and

[X]IW is the concentration of the compound inthe interstitial water (as gm/L) (Pavlou1987), or it can be reasonablyaccurately der ived from theoctanol-water partition coefficientaccording to the formula developed by DiToro et al (1985)(in OMOE 1988).

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log10 KOC + 0.00028 +0.983 log10 (KOW)

The KOW value used is derived by taking thegeometric mean of the available KOW values.

Both measured and calculated KOW values canbe used to derive a KOC and a number ofvalues are required to estimate the KOW used.

KOC values should be calculated fromlaboratory derived sediment-water partitioncoefficients whenever possible, rather thanfrom values derived from the octanol-waterpartition coefficient (KOW).

Since the No Effect Level Guidelines makeuse of the PWQO/Gs which employ safety factorsto ensure conservative levels, it is anticipated thatthe sediment guidelines derived from these will beconservative as well. While the distribution ofnon-polar organics in the pre-colonial sedimenthorizon should technically be zero, it is recognizedthat a certain amount of sediment contaminationhas occurred from remote sources throughatmospheric inputs Since guidelines set belowthese background levels would be impractical, thebackground levels must form the lower limits ofany sediment quality guidelines. To this end,Background levels for the non-polar organics areprovided in this document for comparativepurposes. These are based on the average of theupper Great Lakes, deep basin surficial (top 5 cm)sediment concentrations, or in some cases, onconcentrations in bluff materials. It is expectedthat where the No Effect Level guidelines derivedby the partitioning method fall below thesebackground levels, the background levels willprovide the practical lower limit for managementpurposes.

The deep basin surficial sedimentconcentrations from the Upper Great Lakes can beconsidered as representative of atmosphericinputs of the persistent (generally nonpolar)organics. Table 5 gives the background levels forthose compounds for which upper Great Lakeslevel have been calculated, and these can beconsidered as normal background levels formanagement purposes. This is not to beconstrued as a tacit acceptance of this level ofcontamination, but merely recognizes theubiquitous distribution of these contaminants.

4.4.2 THE LOWEST EFFECT LEVEL

The Lowest Effect Level is the level at whichactual ecotoxic effects become apparent. It isderived using field-based data on theco-occurrence of sediment concentrations andbenthic species. The Screening LevelConcentration method described in the previoussection is used for all types of contaminants.

The calculation of the SLC is a two stepprocess and is calculated separately for eachparameter. In the first step, for each parameterthe individual SLCs (termed Species SLCs) arecalculated for each of the benthic species. Thesediment concentrations at all locations at whichthat species was present are plotted in order ofincreasing concentration (Figure la). From thisplot, the 90th percentile of this concentrationdistribution is determined. The 90th percentile waschosen to provide a conservative estimate of thetolerance range for that species. This would serveto eliminate extremes in concentrations that maybe due to specific and unusual sedimentcharacteristics. The 90th percentile is that locusbelow which 90 percent of the sedimentconcentrations fall.

In the second step, the 90th percentiles for allof the species present are plotted, also in order ofincreasing concentration (Figure 1b). From thisplot, the 5th percentile and the 95th percentile arecalculated. These represent the concentrationsbelow which 5 percent and 95 percent of theconcentrations fall.

1. Metals, Nutrients, and Polar Organics.

Calculate the 5th percentile of the SLC basedon bulk-chemistry sediment data. Since theguidelines are derived for province-wideapplication, the locations used should span a widerange of geographical areas within Ontario ofvarying sediment concentrations of thecontaminant. It is important to ensure that bothhigh sediment concentrations as well as lowconcentrations are used in the data set to ensurethe result is not biased towards one end or theother, since this could bias the resulting SSLC. Aminimum of 10 observations would be required tocalculate a SSLC for any one species. Thisrelatively low minimum has been chosen so as notto exclude less common species, or moreimportantly, the more sensitive species that maynot be present at the more contaminated sitesand thus may not be represented at the majority

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of sites.

A minimum of 20 SSLCs (i.e. 20 species) would berequired for calculation of an SLC.

2. Non-polar Organics

Calculate the SLC as above, but usingcontaminant concentrations normalized tothe organic carbon content of the sediments(i.e. mass of contaminant/mass of organiccarbon as expressed by TOC).

The organic carbon-normalized sedimentcontaminant concentrations are convertedback to a bulk sediment concentrationassuming a 1% TOC. A limit of 1% TOC hasbeen imposed on the calculation sincecalculations using the SLC approach haveshown that this is the lowest effect level oforganic carbon in the sediment.

The Ministry also recognizes that certainparameters addressed in these guidelines, such asthe trace metals, occur naturally in aquaticenvironments. In an area as geologically diverseas Ontario, natural sediment levels can varyconsiderably from one region of the province toanother as a result of differences in local geology.Therefore, the Ministry realizes that certain siteswill naturally exceed the Lowest Effect Level. Insuch cases, the local background levels, based onthe pre-colonial sediment horizon, will form thepractical lower limit for management decisions asdescribed in the Implementation Section of thisdocument.

Calculation of Site-Specific Background:

The mean of 5 surficial sediment samples(top 5 cm) taken from an area contiguous tothe area under investigation, but unaffectedby any current or historical point sourceinputs.

or:

The mean of 5 samples taken by a sedimentcore from the pre-colonial sediment horizon.The pre-colonial horizon is generallydetermined as the sediment below theAmbrosia sediment horizon. Except in areasof high sedimentation, such as river mouths,this can be estimated as that sediment lyingbelow the 10 cm sediment depth.

4.43 THE SEVERE EFFECT LEVEL

This level represents contaminant levels insediments that could potentially eliminate most ofthe benthic organisms. It is obtained bycalculating the 95th percentile of the SLC (the levelbelow which 95% of all SSLCs fall).

1. Metals, Nutrients, and Polar Organics

Calculate the 95th percentile of all SSLCsusing the bulk chemistry values.

2. Non-polar Organics

Calculate the SLC as for the metals, butnormalizing the data to the organic carboncontent (TOC) of the sediments. TheTOC-normalized SLC is then converted to abulk sediment value at the time ofapplication to a specific site, based on theactual TOC concentration of the sediments atthat site (to a maximum of 10%, the 95%SLC guideline for TOC (Table 1)).

The selected guidelines are inferred values,based on available data and are subject torevision as new data become available.Subsequent revisions will follow the same logicalselection process, though using an expanded database.

4.5 DATA REQUIREMENTS

A PWQO or PWQG is required for settinglevels according to the partitioning approach. Inorder to maintain consistency between sedimentand water quality guidelines, levels set by otheragencies will not be used.

At least three estimates of partitioningcoefficients would be required to set a guidelineusing the partitioning approach. Guidelines basedon fewer than the minimum number of estimateswould be regarded as tentative.

The range of contaminant concentrations forthe SLC calculations should span at least twoorders of magnitude and include data from bothheavily contaminated areas and relatively cleanareas. Data from dean areas are needed to ensurethat sensitive species are included in the SLCcalculation, while heavily contaminated areas areneeded to ensure that the full tolerance range of

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all the species is covered.

The database for the SLC calculations shouldbe based on primarily benthic infaunal species andshould minimize the reliance on epibenthicspecies. A minimum of 75% benthic infaunalspecies would be required to ensure that theobserved effects are from sediment associatedcontaminants and not from water column effects.

Consistency in the species data used has tobe ensured. This requires checking the data forsynonymies, unusual species distributions, andlevel of identification. The minimum acceptabletaxonomic level would be the genus, provided thatspecies level identifications were also included inthe data set from which the information wasderived. Data using only generic levelidentifications could not be used.

The SLC database must include a large rangeof areas sampled in order to minimise the effectsof unmeasured but co-varying contaminants.Since these are unlikely to occur in the samerelation at all other areas, the effects of othercontaminants can be reduced or excluded if asufficiently large number of different areas areincluded.

A minimum of 10 observations are requiredto calculate an SSLC. A minimum of 20 SSLCs arerequired to calculated an SLC. This low numberhas been chosen so as not to exclude the lesscommon or more sensitive species that may notbe present at more highly contaminated sites.

REFERENCES

Bedard, D., A. Hayton and D. Persaud. 1992.Laboratory Sediment Biological TestingProtocol. Ont. Ministry of Environment.Toronto. 26 pp.

Hayton, A., D. Persaud and R. Jaagumagi. 1992.Fill Quality Guidelines for Lakefilling inOntario: Application of Sediment and WaterQuality Guidelines to Lakefilling. Ont. Ministryof the Environment. Toronto. 20 pp.

International Joint Commission (IJC). 1983.Report on Great Lakes Water Quality.Appendix. Dredging Subcommittee Report.Windsor, Ontario.

International Joint Commission (IJC). 1985. 1985Report on Great Lakes Water Quality. Great

Lakes Water Quality Board. 212 p.

International Joint Commission (IJC). 1987.Guidance on Characterization of ToxicSubstances Problems in Areas of Concern inthe Great Lakes Basin. Report of theSurveillance Work Group to the Great LakesWater Quality Board. Windsor, Ontario.

Jaagumagi, R. 1992a. Development of the OntarioProvincial Sediment Quality Guidelines forArsenic, Cadmium, Chromium, Copper, Iron,Lead, Manganese, Mercury, Nickel, and Zinc.Ont Ministry of the Environment. Toronto. 46pp.

Jaagumagi, R. 1992b. Development of the OntarioProvincial Sediment Quality Guidelines forPCBs and the Organochlorine Pesticides. Ont.Ministry of the Environment. Toronto. 82 pp.

Jaagumagi, R. 1993. Development of the OntarioProvincial Sediment Quality Guidelines forPolycyclic Aromatic Hydrocarbons (PAH).Ont. Ministry of the Environment. Toronto.79 pp.

Long, E.R. and L.G. Morgan. 1990. The Potentialfor Biological Effects of Sediment-SorbedContaminants Tested in the National Statusand Trends Program. NOAA Tech Memo. NOSOMA 52. 175 pp.

Neff, J.M., DJ. Bean, B.W. Cornaby, R.M. Vaga,T.C. Gulbransen & J.A. Scanlon. 1986.Sediment Quality Criteria MethodologyValidation: Calculation of Screening LevelConcentrations from Field Data. BattelleWashington Environmental Program Officefor U.S. EPA. 60 p.

Ontario Ministry of the Environment (MOE) 1983.Handbook of Analytical Methods forEnvironmental Samples. Vol I and U. OMOE,Toronto.

Ontario Ministry of the Environment (MOE). 1984.Water Management: Goals, Policies,Objectives and Implementation Procedures ofthe Ministry of the Environment. Revised May1984. 70 p.

Ontario Ministry of the Environment (MOE). 1987.Development of Sediment Quality Objectives.Phase I - Options. Prepared by BeakConsultants Ltd.

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Ontario Ministry of the Environment (MOE). 1988.

Development of Sediment Quality Guidelines.Phase II - Guideline Development. Preparedby Beak Consultants Ltd.

Ontario Ministry of the Environment (OMOE).1990. Ontario's Water Quality ObjectiveDevelopment Process. Draft. Ont. Ministry ofthe Environment. Toronto. 67 pp.

Persaud, D. & T. Lomas. 1987. In-Place PollutantsProgram - Volume II Background andTheoretical Concepts. Ont. Ministry of theEnvironment. Toronto. 34 p.

Persaud, D. & W.D. Wilkins. 1976. Evaluating

Construction Activities Impacting On WaterResources. Ont. Ministry of the Environment.Toronto.

Pavlou, S.P. & D.P. Weston. 1984. InitialEvaluation of Alternatives for Development ofSediment Related Criteria for ToxicContaminants in Marine Waters (PugetSound). Phase II: Development and Testingof the Sediment-Water EquilibriumPartitioning Approach. Report prepared byJAB Associates for U.S. EPA. 89 p.

Tetra Tech Inc. 1986. Development of SedimentQuality Values for Puget Sound. Vol. 1. PugetSound Dredged Disposal Analysis Report.129 p.

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Fig 1: SCREENING LEVEL CONCENTRATION CALCULATION

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Figure 2: Application of Provincial Sediment Quality Guidelines to Sediment Assessment.

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Figure 3: Application of Provincial Sediment Quality Guidelines to Dredging Activities

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